Community Corner

The Truth about Ticks and Lyme Disease in San Mateo County

Find out how many people get Lyme disease in San Mateo County and how dangerous ticks are.





Written by Jacob Bourne and Jennifer Squires

Ticks pose a significant danger to both pets and humans in California.

The blacklegged tick (scientifically known at the Ixodes pacificus), which is not uncommon across the state, carries Lyme Disease because it can contain the potentially fatal agent Borrelia burgdorferi.

Lyme disease starts as a tick bite and can develop into a rash, arthritis, severe headache, temporary paralysis, numbness, memory loss, mood swings and heart problems. 

The California Department of Public Health has compiled data on Lyme disease and tick prevalence for every county in the state. Check out the interactive map above to see how San Mateo County compares to the rest of the state.

According to the map, from 2002-2011, there were 0.31 cases of Lyme disease per 100,000 people per year in San Mateo County. The year with the most Lyme diagnoses was 2003, when five San Mateo County residents got the disease. In 2007, there were no new cases of Lyme disease in the county. 

From 1985 until 2013, the department collected 1,069 blacklegged ticks in San Mateo County to test them for the Lyme disease agent. Of that population, 2.1 percent of the adult ticks and 2.6 percent of the nymphal ticks tested positive.

With just over two percent of adult and nymphal ticks carrying the Lyme disease agent in San Mateo County over the past 28 years, a tick bite is certainly not an automatic diagnosis. However, if you are bitten by a tick, contact a doctor immediately to get further instructions. Many doctors will prescribe antibiotics to treat the area and prevent Lyme disease.

San Mateo is far from the most dangerous in the state as far as ticks and Lyme disease are concerned. Just south in Santa Cruz County, there have been 1.68 new cases per 100,000 people per year since 2002. Up in Trinity County, the number is up at 6.53 per 100,000 people per year.

Have you noticed ticks around lately? Any good ideas to prevent tick bites? Tell us in the comments!


Get more local news delivered straight to your inbox. Sign up for free Patch newsletters and alerts.

We’ve removed the ability to reply as we work to make improvements. Learn more here